When a suspicious tissue mass is discovered in a patient's breast through examination, ultrasound, MRI, X-ray imaging or the like, it is often necessary to perform a biopsy procedure to remove one or more samples of that tissue in order to determine whether the mass contains cancerous cells. A biopsy may be performed using an open or percutaneous method.
An open biopsy is performed by making a large incision in the breast and removing either the entire mass, called an excisional biopsy, or a substantial portion of it, known as an incisional biopsy. An open biopsy is a surgical procedure that is usually done as an outpatient procedure in a hospital or a surgical center, involving both high cost and a high level of trauma to the patient. Open biopsy carries a relatively higher risk of infection and bleeding than does percutaneous biopsy, and the disfigurement that sometimes results from an open biopsy may make it difficult to read future mammograms. Further, the aesthetic considerations of the patient make open biopsy even less appealing due to the risk of disfigurement. Given that a high percentage of biopsies show that the suspicious tissue mass is not cancerous, the downsides of the open biopsy procedure render this method inappropriate in many cases.
Percutaneous biopsy, to the contrary, is much less invasive than open biopsy. Percutaneous biopsy may be performed using fine needle aspiration (FNA) or core needle biopsy. In FNA, a very thin needle is used to withdraw fluid and cells from the suspicious tissue mass. This method has the advantage that it is very low-pain, so low-pain that local anesthetic is not always used because the application of it may be more painful than the FNA itself. However, a shortcoming of FNA is that only a small number of cells is obtained through the procedure, rendering it relatively less useful in analyzing the suspicious tissue and making an assessment of the progression of the cancer if the sample is found to be malignant.
Core needle biopsy provides for removal of a small tissue sample that allows a pathological assessment of the tissue, including an assessment of the progression of any cancerous cells that are found. The following patent documents disclose various biopsy devices and are incorporated herein by reference in their entirety: U.S. Pat. No. 6,273,862 issued Aug. 14, 2001; U.S. Pat. No. 6,231,522 issued May 15, 2001; U.S. Pat. No. 6,228,055 issued May 8, 2001; U.S. Pat. No. 6,120,462 issued Sep. 19, 2000; U.S. Pat. No. 6,086,544 issued Jul. 11, 2000; U.S. Pat. No. 6,077,230 issued Jun. 20, 2000; U.S. Pat. No. 6,017,316 issued Jan. 25, 2000; U.S. Pat. No. 6,007,497 issued Dec. 28, 1999; U.S. Pat. No. 5,980,469 issued Nov. 9, 1999; U.S. Pat. No. 5,964,716 issued Oct. 12, 1999; U.S. Pat. No. 5,928,164 issued Jul. 27, 1999; U.S. Pat. No. 5,775,333 issued Jul. 7, 1998; U.S. Pat. No. 5,769,086 issued Jun. 23, 1998; U.S. Pat. No. 5,649,547 issued Jul. 22, 1997; U.S. Pat. No. 5,526,822 issued Jun. 18, 1996; and US Patent Application 2003/0199753 published Oct. 23, 2003 to Hibner et al.
It is known in the art for core needle biopsy devices to include a firing mechanism which allows the needle and a cutter to thrust forward in order to obtain a tissue sample.
Frequently, a surgeon may encounter an area of dense tissue that is more difficult to penetrate than the surrounding tissue during core needle biopsy. In particular, the lesion or tissue mass being targeted in the biopsy procedure may be difficult to penetrate, requiring the physician to push the biopsy needle with considerable force and/or speed in an attempt to penetrate the lesion and collect a sample.
When encountering such an area of dense tissue, it is common for surgeons using the type of firing core needle biopsy device described above to fire the device in order to penetrate the lesion and obtain a sample. However, due to the length of the firing stroke of such devices, which can be as long as 0.75 inches, it is nearly impossible for the surgeon to control the travel of the needle after firing.
The long needle stroke may cause uncertainty as to the needle tip location post fire. This may cause the surgeon to obtain a sample from the wrong area. In addition to missing the targeted tissue, long firing strokes may cause the needle to puncture the chest wall or pierce the skin, particularly when the targeted area is near the patient's chest wall. Even if the skin is not pierced, the long travel of the needle, along with the likelihood that the needle will be pushed off course by the force of the firing stroke, may lead to needlessly increased trauma for the patient.
Based on surgeons' use of the long sampling stroke feature of current devices to aid in penetrating tissue lesions, it is clear that the medical community sees the benefit of firing assistance when inserting a probe to the desired location. However, the current devices incorporating a sampling stroke are not intended for, nor properly designed to, aid in penetration of dense tissue.
Consequently, a significant need exists for a core needle biopsy device that aids the surgeon in penetrating areas of dense tissue without utilizing an excessively long firing stroke that may throw the biopsy device off course, causing the patient unnecessary trauma and possibly causing the surgeon to obtain a sample from outside the targeted area. A need also exists for a device capable of a firing stroke to assist in penetrating dense tissue to properly locate the needle before advancing the cutter through the needle.